Another great example of how science fiction becomes the face of science and Hollywood’s strange relationship This latest invention is very similar to James Cameron’s popular sci-fi thriller, Terminator 2. The 1991 film featured the T-1000, a shape-shifting liquid metal robot. Although the liquid metal robot is still in its early stages, it is still a step in that direction.
While the development of soft robots that can perform a variety of functions, including shape-shifting, is nothing new, this is the first time a new approach has been attempted—one that avoids the challenges of previous technologies. Although many current robots are magnetically steerable under the new approach, they are either flexible but rigid, which does not allow them to move in small spaces, or magnetofluids, which are fluid but cannot withstand large loads.
Returning to the most recent research, a best-of-both-worlds approach is required: developing a robot that not only provides strength and agility, but also the flexibility to push and swing to new locations.
Interestingly, scientists were inspired by nature, where sea cucumbers can change their stiffness very quickly and vice versa. But they had to reproduce this behaviour in soft material systems. This led them to create a newly developed phase transfer material called “magnetoactive liquid-solid phase transition material,” or MPTM.
Instead of relying on an external heat source to shape and transform, the magnetic field generates its own heat on the robot through induction. These robots do not require the thousands of components needed in a complex robot like ATLAS and are made of only two materials: magnetic neodymium-iron-boron microparticles embedded in gallium, a metal that melts at 29.8 °C.
Gallium is filled with magnetic particles that allow it to be moved by a permanent magnet. In solid form, the material can be moved by a magnet at a speed of about 1.5 metres per second. In addition, advanced gallium can withstand loads up to 10,000 times its own weight. However, external magnets can affect the liquid form, causing it to stretch, crack, and melt.
Controlling the movement of the liquid is more difficult, however, because the gallium magnetic particles can rotate freely and have misaligned poles due to melting. As a result, the particles move in different directions when they come into contact with the magnet due to their different orientations. The research team conducted a number of experiments to put their invention’s applications to the test.
In the first, a toy dungeon escaped from a dungeon by melting through the bars and regaining its original shape using a mould that was placed behind the bars. Another, more practical application was to remove a small ball from the abdomen of a model person by fusing the foreign body around it before exiting the organ—both shown in the video above.
In another demonstration of its usefulness in industrial applications, a robot crawled into a machine and replaced a missing screw by simply “melting the threaded screw into the base” before it solidified again. While the robot offers impressive precision while moving with an external energy source in the form of a magnetic field, questions remain about its biomedical applications, for example, controlling an externally generated magnetic field in the human body. Regardless, this is a brave moment for scientists.
Complete research was published in the Journal of Matter.
